Will Human-Animal Hybrids Make Medicine or Monsters?

The quest to build better people.
May 13 2013 7:45 AM

Manimal Rights

How far should science go in making human-animal chimeras?

(Continued from Page 1)

Yet experiments like these are going forward just the same. In just the past few months, scientists at the University of Wisconsin and the University of Rochester have published data on their human-animal neural chimeras. For the Wisconsin study, researchers injected mice with an immunotoxin to destroy a part of their brains—the hippocampus—that's associated with learning, memory, and spatial reasoning. Then the researchers replaced those damaged cells with cells derived from human embryos. The cells proliferated and the lab chimeras recovered their ability to navigate a water maze.

For the Rochester study, researchers implanted newborn mice with nascent human glial cells, which help support and nourish neurons in the brain. Six months later, the human parts had elbowed out the mouse equivalents, and the animals had enhanced ability to solve a simple maze and learn conditioned cues

These protocols might run afoul of the anti-hybrid laws, and perhaps they should arouse some questions. These chimeric mice may not be human, or even really humanish, but they're certainly one step further down the path to Algernon. It may not be so long before we're faced with some hairy bioethics: What rights should we assign to mice with human brains?

Advertisement

All that has to do with sticking human parts in beasts. Transplants also go the other way: Heart valves and ligaments can be extracted from a pig, stripped of excess porcine cells, and implanted in a person. In the not-too-distant future we may see more substantive forms of xenotransplantation, particularly from pigs that have been genetically engineered to make their parts more amenable to human use. (These animals lack a pig-specific protein that induces a strong immune response from people.) Transplanted pig corneas and pancreatic cells will be next, and we might see hearts and kidneys one day as well.

These procedures haven't generated much angst, except perhaps from orthodox rabbis. Presumably that's because they'd leave us with a fully human brain, and that's where we like to think our deepest personhood resides. Transplanted pig parts also fail to violate a taboo against enhancement: They're therapies, not upgrades—a way to mend a broken part.

What if animal organs, cells, or DNA could make us faster, stronger, or more adept? The Department of Defense has dabbled with the notion of dosing humans with bacteria taken from a pig's digestive tract. This research program, known as "Intestinal Fortitude," could in theory help a solder to digest cellulose or otherwise survive on "non-traditional foodstuffs."

No one has transfected a living human with nonhuman genes in an effort to bestow cheetah-speed or night vision, or tested radioactive spider-bites in a controlled, laboratory setting. "Let's put it this way," says Maxwell Mehlman, a bioethicist at Case Western and author of a book on transhumanism, "we can't even figure out a good way of gene doping using human genes."

One hundred years ago, a doctor named John Brinkley started implanting patients with goat testicles as a way to make them virile. These days, quack physicians promise to invigorate us with deer antlers. The technology may change, but the dream of manimal enhancement never goes away.

Read more from Slate’s Superman package: Is human enhancement cheating, everyday technologies that already give us superpowers, and would you use superpowers for good or evil?

TODAY IN SLATE

Politics

The Democrats’ War at Home

How can the president’s party defend itself from the president’s foreign policy blunders?

Congress’ Public Shaming of the Secret Service Was Political Grandstanding at Its Best

Michigan’s Tradition of Football “Toughness” Needs to Go—Starting With Coach Hoke

A Plentiful, Renewable Resource That America Keeps Overlooking

Animal manure.

Windows 8 Was So Bad That Microsoft Will Skip Straight to Windows 10

Politics

Cringing. Ducking. Mumbling.

How GOP candidates react whenever someone brings up reproductive rights or gay marriage.

Building a Better Workplace

You Deserve a Pre-cation

The smartest job perk you’ve never heard of.

Hasbro Is Cracking Down on Scrabble Players Who Turn Its Official Word List Into Popular Apps

Florida State’s New President Is Underqualified and Mistrusted. He Just Might Save the University.

  News & Politics
Politics
Sept. 30 2014 9:33 PM Political Theater With a Purpose Darrell Issa’s public shaming of the head of the Secret Service was congressional grandstanding at its best.
  Business
Moneybox
Oct. 1 2014 8:34 AM Going Private To undertake a massively ambitious energy project, you don’t need the government anymore.
  Life
Quora
Oct. 1 2014 9:13 AM What Is It Like to Be an Egyptologist?
  Double X
The XX Factor
Sept. 30 2014 12:34 PM Parents, Get Your Teenage Daughters the IUD
  Slate Plus
Behind the Scenes
Sept. 30 2014 3:21 PM Meet Jordan Weissmann Five questions with Slate’s senior business and economics correspondent.
  Arts
Brow Beat
Oct. 1 2014 8:46 AM The Vintage eBay Find I Wore to My Sentencing
  Technology
Future Tense
Sept. 30 2014 7:00 PM There’s Going to Be a Live-Action Tetris Movie for Some Reason
  Health & Science
Bad Astronomy
Oct. 1 2014 7:30 AM Say Hello to Our Quasi-Moon, 2014 OL339
  Sports
Sports Nut
Sept. 30 2014 5:54 PM Goodbye, Tough Guy It’s time for Michigan to fire its toughness-obsessed coach, Brady Hoke.